1. Field of the Invention
The present invention relates generally to semiconductor manufacturing and, more particularly, to a method and apparatus for providing a confinement ring drive that provides proportional spacing between the confinement rings over a travel range.
2. Description of the Related Art
During the manufacturing of semiconductor-based devices, it is common to deposit layers of material onto a substrate. Each of the layers of material may undergo an etching process. Etching of the layers may be accomplished by a wide variety of techniques including plasma-enhanced etching.
The plasma etchers performing these operations may include confinement rings to confine the plasma within a region of the etch chamber. The confinement rings serve to confine the plasma and also protect the chamber walls. However, the current systems are not well suited to adjust to changes within the etch chamber during the processing operation. In particular, the current systems cannot maintain equal gaps between the confinement rings because of restrictions in the confinement ring drive system. The lack of capability to proportionally adjust the confinement rings may result in a change of the gas flow dynamics, a lack of reproducibility between successive etch operations, e.g., in an etch rate, or the plasma going unconfined, which results in the chamber walls being attacked by the plasma.
In view of the foregoing, there is a need for a method and apparatus that provides for uniform movement of the confinement rings over a range of travel of the confinement rings.